From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 829B5C169C4 for ; Wed, 6 Feb 2019 19:00:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5C61220823 for ; Wed, 6 Feb 2019 19:00:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726836AbfBFTA1 (ORCPT ); Wed, 6 Feb 2019 14:00:27 -0500 Received: from faui40.informatik.uni-erlangen.de ([131.188.34.40]:46668 "EHLO faui40.informatik.uni-erlangen.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726561AbfBFTA1 (ORCPT ); Wed, 6 Feb 2019 14:00:27 -0500 Received: from faui49copter1 (faui49copter1.informatik.uni-erlangen.de [131.188.42.149]) by faui40.informatik.uni-erlangen.de (Postfix) with SMTP id 93F36548859; Wed, 6 Feb 2019 20:00:21 +0100 (CET) Received: by faui49copter1 (sSMTP sendmail emulation); Wed, 06 Feb 2019 20:00:21 +0100 From: Andreas Ziegler To: Steven Rostedt Cc: Ingo Molnar , Masami Hiramatsu , linux-kernel@vger.kernel.org, Andreas Ziegler Subject: [PATCH v2 RESEND] tracing: probeevent: Correctly update remaining space in dynamic area Date: Wed, 6 Feb 2019 20:00:13 +0100 Message-Id: <20190206190013.16405-1-andreas.ziegler@fau.de> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190122152634.18957-1-andreas.ziegler@fau.de> References: <20190122152634.18957-1-andreas.ziegler@fau.de> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit 9178412ddf5a ("tracing: probeevent: Return consumed bytes of dynamic area") improved the string fetching mechanism by returning the number of required bytes after copying the argument to the dynamic area. However, this return value is now only used to increment the pointer inside the dynamic area but misses updating the 'maxlen' variable which indicates the remaining space in the dynamic area. This means that fetch_store_string() always reads the *total* size of the dynamic area from the data_loc pointer instead of the *remaining* size (and passes it along to strncpy_from_{user,unsafe}) even if we're already about to copy data into the middle of the dynamic area. Fixes: 9178412ddf5a ("tracing: probeevent: Return consumed bytes of dynamic area") Signed-off-by: Andreas Ziegler Acked-by: Masami Hiramatsu --- v2: follow coding guidelines for braces kernel/trace/trace_probe_tmpl.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace_probe_tmpl.h b/kernel/trace/trace_probe_tmpl.h index 5c56afc17cf8..4737bb8c07a3 100644 --- a/kernel/trace/trace_probe_tmpl.h +++ b/kernel/trace/trace_probe_tmpl.h @@ -180,10 +180,12 @@ store_trace_args(void *data, struct trace_probe *tp, struct pt_regs *regs, if (unlikely(arg->dynamic)) *dl = make_data_loc(maxlen, dyndata - base); ret = process_fetch_insn(arg->code, regs, dl, base); - if (unlikely(ret < 0 && arg->dynamic)) + if (unlikely(ret < 0 && arg->dynamic)) { *dl = make_data_loc(0, dyndata - base); - else + } else { dyndata += ret; + maxlen -= ret; + } } } -- 2.17.1